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Phosphorylation-inducing chimeric small molecules (PHICS) can enable a kinase to act at a new cellular location or phosphorylate non-native substrates (neo-substrates)/ sites (neo-phosphorylations).

Ionophores transport ions across biological membranes and have wide-ranging applications, but a platform for their rapid development does not exist. We report a platform for developing ionophores from metal-ion chelators, which are readily available with wide-ranging affinities and specificities, and structural data that can aid rational design. Specifically, we finetuned the binding affinity and lipophilicity of a Zn(II)-chelating ligand by introducing silyl groups proximal to the Zn(II)-binding pocket, which generated ionophores that performed better than most of the currently known Zn(II) ionophores. Furthermore, these silicon-based ionophores were specific for Zn(II) over other metals and exhibited better antibacterial activity and less toxicity to mammalian cells than several known Zn(II) ionophores, including pyrithione. These studies establish rational design principles for the rapid development of potent and specific ionophores and a new class of antibacterial agents. A general approach to rationally design Zn(II) ionophores from Zn(II) chelator by incorporation of silyl-based groups is reported. These ionophores were more potent than several reported Zn(II) ionophores. Furthermore, these Zn(II) ionophores demonstrated selective antibacterial activity and lower mammalian cell toxicity compared to the known ionophore, pyrithione.

Proteolysis Targeting Chimeras (PROTACs), a class of heterobifunctional molecules that recruit target proteins to E3 ligases, have gained traction for targeted protein degradation. However, pomalidomide, a widely used E3 ligase recruiter in PROTACs, can independently degrade other targets, such as zinc-finger (ZF) proteins, that hold key functions in normal development and disease progression. This off-target degradation of pomalidomide-based PROTACs raises concerns about their therapeutic applicability and long-term side effects. Therefore, there is a crucial need to develop rules for PROTAC design that minimize off-target degradation. In this study, we developed a high-throughput platform that interrogates the off-target degradation of ZF domains and discovered, using this platform, that PROTACs with the current design paradigm induce degradation of several ZF proteins. To identify new rules for PROTAC design, we generated a library of pomalidomide analogs that allowed systematic exploration of the impact of positional isomerism (e.g., C4 and C5 positions of the phthalimide ring), hydrogen bonding, steric and hydrophobic effects on propensities for ZF protein degradation. We found that modifications of appropriate size on the C5 position reduced off-target ZF degradation. We validated these results using immunoblotting, target engagement, and global mass spectrometric studies. We applied our newfound design principles on a previously developed ALK oncoprotein-targeting PROTAC and generated PROTACs with enhanced potency and minimal off-target degradation. We envision the reported off-target profiling platform and pomalidomide analogs will find utility in design of specific PROTACs.

A highly efficient catalytic method has been developed for asymmetric radical cyclopropanation of alkenes with in situ-generated α-heteroaryldiazomethanes via Co(II)-based metalloradical catalysis (MRC). Through fine-tuning the cavity-like environments of newly-synthesized D(2)-symmetric chiral amidoporphyrins as the supporting ligand, the optimized Co(II)-based metalloradical system is broadly applicable to α-pyridyl and other α-heteroaryldiazomethanes for asymmetric cyclopropanation of wide-ranging alkenes, including several types of challenging substrates. This new catalytic methodology provides a general access to valuable chiral heteroaryl cyclopropanes in high yields with excellent both diastereoselectivities and enantioselectivities. Combined computational and experimental studies further support the underlying stepwise radical mechanism of the Co(II)-based olefin cyclopropanation involving α- and γ-metalloalkyl radicals as the key intermediates.

The paper attempts to understand the macroresponse of fiber-reinforced polymer (FRP) confined concrete in terms of mesolevel interactions. Cylindrical specimens are modeled using a three-di...

Systematic investigation was carried out to understand the effect of plate-to-pipe forming (U-bending) strain on the microstructure and mechanical properties of X80 linepipe steel and to establish a structure-property correlation. Finite element simulation predicted the von Mises stress state and through-thickness residual stress distribution. Transmission electron microscopy and electron back scattered diffraction studies detected the local strain gradients, which were verified by nanoindentation testing along with the estimation of through-thickness residual stress. Both yield strength and tensile strength increased after cold-bending operation due to dislocation generation. Also, post-uniform elongation increased, especially at inner diameter (ID) portion due to an overall more dislocation interaction. In the presence of compressive residual stress, ID sample revealed improved impact toughness than the as-received (AR) one at all tested temperatures in the range of −80 °C to room temperature. Low temperature (-80 °C) impact toughness increased by ~16% even at outer diameter (OD) of the pipe, despite the presence of a tensile residual stress state. This improvement in toughness is contributed by many factors, such as the increase in critical stress for yielding, the decrease in crystallographic unit size, less availability of potential sites for cleavage crack initiation, texture strengthening, and crack-divider type fissure formation.

A Pd(II)-catalyzed highly regioselective γ-chalcogenation, thioarylation, and selenoarylation of aliphatic carboxylic acids has been demonstrated. The present protocol provides a direct access to make structural modifications of α-amino acids such as valine, isoleucine, and tert-leucine with high diastereoselectivity (up to 52:1). Sequential heterobifunctionalizations have been carried out at γ-sp3 C–Hs, resulting in desymmetrization of quaternary centers. The applicative potential of the chalcogenated products was exhibited by using them as precursors for the synthesis of the biologically relevant benzothiepinone moiety. Preliminary studies were carried out to gain insights into the mechanism.

Co-extrusion is one of the most effective processes for manufacturing long polymeric profiles with two textures with different constituent rubber compound’s inherent properties. Typically, two rubber compounds are amalgamated with each other to construct hard and soft surfaces. This study investigates the die swell characteristics while extruding the two rubber components using the proper material properties. Herein, the EPDM rubber-based compound’s thermal and rheological parameters have been identified to predict the extrudate’s overall deformation profiles during the extrusion molding process. Carreau-Yasuda and Arrhenius approximate law exhibited an excellent fit for a wide range of shear rates with the experimental data. Finally, the extrudate’s overall deformation has been simulated using finite element software (ANSYS Polyflow®) at real processing conditions along with the boundary conditions (inlet, die wall, Interfaces, extrudate free surface, profile cross-section). Furthermore, numerical results generated from the simulation have been cross-verified with the experimental results for a complex-shaped rubber profile, and a good agreement with an efficiency of > 98.5% was obtained.

The paper extends the formal structure of the fabric based analysis of cohesion-less granular materials to cemented granular materials such as concrete. The stress-fabric and strain-fabric relationships are derived, and both are seen to be sensitive to particle angularity and maximum particle size. The contributions of the isotropic and anisotropic parts of the micro structural stress and strain are identified and a recently developed discrete element capability used to investigate their separate contributions to the macro behaviour in uniaxial compression. The anisotropic part of the micro-structural stress plays a dominant role in determining the peak strength. However, post peak ductility is largely controlled by the isotropic part. Remarkably fabric anisotropy, which depends strongly on particle angularity, is seen to result in higher hydrostatic pressures. This strengthens the “internal confinement mechanism” and accounts for the superior strength of specimens with angular aggregates observed in experiments.

A Pd(II)-catalyzed protocol for highly regioselective distal γ-C–H silylation and germanylation of aliphatic carboxylic acids is reported. Bidentate 8-aminoquinoline as the directing group was found to stabilize the six-membered palladacycle. A variety of aliphatic carboxylic acids and amino acids were silylated and germanylated in good yields and high diasteroselectivities. Detailed mechanistic studies involving isolation of a Pd(II) intermediate, determination of the reaction rate and order, control experiments, and isotopic labeling and DFT studies were found to be crucial for elucidating the elementary steps involved in this distal aliphatic functionalization.

Summary The effect of heterogeneity in meso level geometric and material properties on tensile strength and size effect in split cylinder specimens is investigated. Critical meso geometric parameters are identified by studying their influence on the evolution of the fracture process zone. A statistical analysis is used to account for dependencies between the parameters. A reversal of the size effect, important for the strength of field specimens, is observed for certain meso geometries. Meso level explanations for this are proposed, and meso geometries likely to show such a reversal are identified. For moderately sized specimens, major trends in the size effect are seen to be almost entirely explained by heterogeneity in the meso geometry.

A palladium(II)-catalyzed protocol for the highly regioselective remote γ-C–H arylation of aliphatic carboxylic acid has been disclosed. The 8-aminoquinoline moiety as an intramolecular bidentate chelator was found to be suitable for this γ-C–H arylation. Various aryl iodides successfully produced the regioselectively mono-arylated products with negligible diarylation. Functional group tolerance and easy-to-handle reaction conditions make this method attractive.

Mizoroki–Heck olefination is one of the most exquisite methods for making carbon–carbon bonds. Numerous methods have been reported for olefination with electronically biased olefins such as acrylates and styrenes. In the absence of suitable bias, olefination with unactivated olefins suffers from regioselectivity issues. Because of these problematic regiochemical outcomes, there are only scattered examples of olefination with unactivated olefins. Both linear-selective and branched-selective protocols , based on control over the selectivity of olefin insertion and β-hydride elimination, have been reported. In this microreview, different branched-selective and linear-selective olefination protocols with unactivated olefins are discussed, starting from the invention of Heck olefination. Throughout this microreview, different aspects associated with olefination protocols – such as the factors underlying selectivity, functional group tolerance and, more specifically, the use of a variety of unactivated olefins – are discussed.

A novel [3+2] cycloaddition between a variety of cyclic ketones and diverse olefins or alkynes can be effectively promoted by copper in combination with the tri-tert-butylphosphine [P(tBu)(3)] ligand. This protocol exhibits excellent selectivity and provides an exemplary set of fused heterocycles in good to excellent yields. Present strategy also represents an extremely simple and atom- economic way to construct substituted fused furans and naphthofurans from readily available starting materials under mild reaction conditions. The utility of the method is further demonstrated by the synthesis of chiral furans from ( R)-(-)-carvone and (S)-(+)-carvone. A plausible mechanism involving the oxidative radical cyclization has been suggested based on experimental observations.

The purposes of this work were: (i) to understand how erosive wear is affected by the random meso structure of concrete, and (ii) to develop a model for erosive wear of concrete structures due to the action of sediment bearing water loads. An aggregate generation algorithm with certain novel features is used to generate a database comprising 400,000 aggregates with varying levels of angularity and flakiness. Using these aggregates, a probabilistic model for mass loss due to aggregate erosion was formulated. A Monte Carlo simulation is used to obtain the time to failure for single aggregates; these were used to obtain an estimate of slurry erosive loss from the concrete structure, where successive layers of aggregates are assumed to satisfy the ergodicity assumption. The mass loss estimates were compared with experimental results for a sediment bearing water jet. A good qualitative match was observed, with both experimental results and probabilistic estimates exhibiting very similar dependence on meso geometry.

A recently developed discrete element capability is used to understand the effect of random variations in aggregate shape and size on tensile cracking in concrete. A procedure to reconstruct the three-dimensional crack surface, and characterize its tortuosity, is proposed. The role of anisotropy in the material fabric, induced by variations in aggregate shape, is studied. Both tensile and compressive strength are seen to be affected by fabric anisotropy, but to different extents and in different ways. Post-peak behaviour in tension is linked to dispersion in the local fabric, characterized by a proposed local fabric tensor. The influence of aggregate shape on fracture process zone geometry is investigated. Overall, aggregate shape appears to be the dominant factor in determining the post-peak response. However aggregate size appears to affect the tensile strength more strongly while its influence on the fracture energy is complicated and subject to two opposing trends.

Bending induced anisotropy in mechanical properties of high-strength high-toughness steel has been investigated considering all possible factors. A 24 mm thick controlled-rolled and continuously-cooled plate of API X80 grade steel was cold-bent at ambient temperature by hydraulic pressure. The sampling was done from different parts of the bent plate. It has been shown by experiments and finite element simulation that the mechanical property anisotropy after cold-bending is mainly governed by the residual stress state and its distribution on the main fracture plane along with the nature of the newly generated dislocations. Additionally, the density of potential sites for cleavage crack initiation can come into the picture at cryogenic temperatures. Overall, anisotropy in tensile property reduced both in inner diameter (ID) and outer diameter (OD) of the bent plate, whereas, anisotropy in toughness minimized only in OD.

An analytical model is developed for fiber-reinforced polymer (FRP) confined hollow circular concrete columns subjected to axial compression to study the effect of cohesive stiffness on confining pressure. The results are corroborated using 3D finite element (FE) analysis. The FE model is used to study the effect of confining stiffness on the strength and mode of failure in hollow columns. For low confining pressures, quasi-brittle failure occurs due to shear banding in the concrete; whereas for confining pressures in excess of a threshold, the response is ductile. Strength and size effect in hollow columns are compared with solid columns with the same outer diameter, FRP thickness and material properties. It is seen that hollow columns have reduced strength and are more susceptible to a size effect than solid columns.

A silver(I) catalyzed regioselective trifluoromethylation of allenes using Langlois's salt (NaOSOCF3 ) is demonstrated. This transformation enables direct expedient access to α-trifluoromethylated acroleins, which are valuable synthons for a number of pharmaceuticals and agrochemicals containing vinyl-CF3 moieties. Versatility of this trifluoromethylation method has been established with good yield and excellent regioselectivity. Preliminary experiments and computational studies were carried out to elucidate the mechanistic insight of this protocol.

A three-dimensional discrete element modelling capability for concrete based on rigid particles of arbitrary shape and size has been developed. The novel particle generation algorithm allows control of particle size, angularity and flakiness. General rigid body kinematics including finite rotations is accounted for, and an explicit time integration algorithm that conserves energy and momentum is implemented. An efficient contact algorithm with several features to increase the efficiency of the contact computations has been developed. This enables the gravity packing problem for arbitrary shaped particles to be solved in reasonable run time. The proposed procedure is used to generate assemblies of concrete specimens of various sizes that are homogeneous and isotropic in the bulk, and can capture the wall effect due to the formwork. The calibrated specimens are seen to be capable of accurately capturing experimentally observed macro stress strain response and failure patterns. The influence of aggregate shape on texture formation in the packed specimen, and on macro strength and failure patterns in hardened concrete, is demonstrated and is seen to be consistent with experimental results.

This paper investigates high-cycle fatigue (HCF) failure in thermomechanically treated (TMT) rebars using fractographic analysis. Most fatigue failures are found to initiate at the root of ...

In order to develop earthquake resistant or blast resistant structures for freezing environmental condition, it is necessary to evaluate the impact toughness and impact transition behaviour of thermo-mechanically treated (TMT) reinforcement steel bars. Considering the difficulty in preparing standard geometry Charpy V-notch specimens from the TMT rebar, a new specimen design, on semi-circular cross-section, is proposed in the present study for the impact testing of rebars. Tensile testing and impact toughness testing have been carried out on the TMT rebar samples of different diameters (10–16 mm) to study the processing-microstructure-mechanical property relationship. Among the investigated rebars, higher section rebar (16 mm) showed the best combination of strength, ductility and impact toughness possibly due to the higher tempered martensite rim fraction and the presence of degenerated pearlite and lower bainite at the core region of that rebar. Large fraction of high-angle boundaries and the presence of gamma-fibre texture could have contributed to the lowest ductile–brittle transition temperature (DBTT) in 12 mm rebar. Impact toughness can also be influenced by the residual stress distribution inside the rebars. Keywords: Reinforcement steel bar, Thermo-mechanical treatment, Rim, Core, Charpy impact testing, Impact transition temperature

A radical based direct C-H iodination protocol for quinolines, quinolones, pyridones, pyridines, and uracil has been developed. The iodination occurs in a C3 selective manner for quinolines and quinolones. Pyridones and pyridines undergo C3 and C5 iodination, while dimethyl uracil undergoes C5 iodination. Scope of the method was demonstrated through the rapid synthesis of both electron rich as well as electron poor heteroaromatic iodides. The protocol was found to be scalable and general, while a mechanism has been proposed.

The effect of size on strength of fiber-reinforced polymer (FRP)-confined cylindrical concrete columns is studied. The specimens studied are self-similar, i.e., all column dimensions as wel...

Biologically and pharmaceutically relevant arylated quinones (Quin-Ar) have been synthesized via direct CH arylation of a variety of phenols using arylboronic acids. An inexpensive, environmentally friendly iron catalyst, ferric sulphate, Fe-2(SO4)(3), was employed in this operationally simple and efficient method.

A generalized Ritz based approach that accounts for pre-buckling bending deformations as well as geometric non-linearity to find the buckling load for thin cylindrical shells under uniform axial compression is proposed. The approach accommodates within a unified framework, based on a shell and spring restraint system, the entire range of boundary conditions: ranging from free boundaries to compliant boundaries. The classical kinematic boundary conditions are recovered as limiting cases. The method involves choice of a single trial function that is invariant with respect to boundary conditions. The proposed approach is validated using existing analytical results, where available, and numerical solutions, otherwise.

Body armors are generally made of several layers of para-aramid fabrics, with Kevlar being the most popular among them. While Kevlar has high strength to weight ratio and sufficient flexibility, the difficulty arises when armors are designed for high threat level. In such cases, ballistic inserts (commonly made of ceramic, metal or composite) are often used in body armor, which make the armor stiffer and bulky. A natural question therefore arises that whether the stiff ballistic inserts can be replaced by something flexible without compromising the strength of the armor. In this context the shear thickening fluid (STF) appears to be an interesting material. The present study is an attempt to numerically investigate the potential of STF in such applications. Towards this, two Kevler-STF composite targets made of Kevlar-STF-Kevlar sandwich composite and STF impregnated Kevlar are considered. Ballistic response of the composite is studied via the coupled Eulerian–Lagrangian (CEL) approach. In the CEL approach, Kevlar yarn is modelled using Lagrangian membrane element and STF is embedded in an Eulerian mesh. Simulations are performed with different projectiles, impact velocities and STF characteristics (shear rate vs viscosity behaviour). In the process the effect of STF in improving ballistic response is brought out.

Effect of imperfections at the interface between concrete and FRP on the strength of FRP confined axially loaded cylindrical concrete columns is investigated, experimentally and numerically. It is seen that the presence of imperfections facilitates localization of deformation, adversely affects the confining capacity of FRP, and reduces the failure load. The influence of size, location and orientation of imperfection on failure load is studied: the orientation and location are found to be more important than size. Critical locations and orientations of the imperfection are found and explained in terms of the mechanics of shear banding in pressure-sensitive elasto-plastic materials.

An economical approach to α-CF3-substituted ketones, which are important intermediates in synthetic and medicinal chemistry, employs olefins and the readily available Langlois reagent (CF3SO 2Na). The reaction is operationally simple, proceeds at room temperature, and exhibits an excellent tolerance toward a wide variety of functional groups. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The arylation of C–H bonds to generate heteroaryl–aryl (Het–Ar) and arylated quinone (Quin–Ar) compounds has received great attention to achieve sustainable goals in synthetic chemistry. Despite significant advances, arylation of a broad range of Het–Ar and Quin–Ar derivatives remains a challenging task. Herein, a variety of heterocycles are arylated by using arylboronic acids in the presence of catalytic amounts of inexpensive Fe(NO3)3. The C-arylated quinone compounds can be prepared by reacting arylboronic acids with either quinone or hydroquinone. The present method is operationally simple, scalable, does not require prefunctionalization of the heterocycle or quinone, and can tolerate a wide variety of functional groups in the coupling partners. These qualities are expected to render this method attractive for academic and industrial use.

Directing group assisted regioselective C-H olefination with electronically biased olefins are well studied. However, the incorporation of unactivated olefins has remained largely unsuccessful. A proper mechanistic understanding of olefination involving unactivated alkenes is therefore essential for enhancing their usage in future. In this article, detailed experimental and computational mechanistic studies on palladium catalyzed C-H olefination with unactivated, aliphatic alkenes are described. The isolation of a Pd(II) intermediates are shown to be effective for elucidating the elementary steps involved in catalytic olefination. Reaction rate and order determination, control experiments, isotopic labeling studies and Hammett analysis have been used to understand the reaction mechanism. The results from these experimental studies implicate β-hydride elimination as the rate-determining step and that a mechanistic switch occurs between cationic and neutral pathway. Computational studies support this interpretation of the experimental evidence and are used to uncover the role of proton on the origins of selectivity.

2-Haloaryl-sec-alkyl unsymmetrical thioureas (Tu) (halo = –F, –Cl) with a catalytic amount of Cu(II) salt get oxidised in situ to their disulfide intermediates followed by an imine-disulfide rearrangement to give thioamidoguanidino (Tag) moieties at room temperature. During this process Cu(II) gets reduced to Cu(I) and forms a complex with the Tag moiety from which Tag moiety can be isolated upon treatment with ammonia. However, when the same reaction was performed at an elevated temperature with a catalytic quantity of Cu(II) salt, Tu bearing o-halogens (–F, –Cl) gave 2-aminobenzothiazoles via a dehalogenative heteroarylation path and not by the Hugerschoff path involving an electrophilic substitution reaction. For thioureas containing reactive ortho halogens (such as –Br, –I) the reaction proceeds at room temperature giving 2-aminobenzothiazoles via a dehalogenative path requiring a catalytic quantity of Cu(II). No transformation of thiourea (Tu) to Tag was observed with Cu(I) salts suggesting the requirement of an oxidising Cu(II) salt for this oxidative transformation. Mild reaction conditions, environmentally benign reagents and solvent, high yields, tolerance of various functional groups are some of the essential features of this methodology.

A novel [3+2] cycloaddition between a variety of cyclic ketones and diverse olefins or alkynes can be effectively promoted by copper in combination with the tri-tert-butylphosphine [P(tBu)

A radical based direct C-H iodination protocol for quinolines, quinolones, pyridones, pyridines, and uracil has been developed. The iodination occurs in a C3 selective manner for quinolines and quinolones. Pyridones and pyridines undergo C3 and C5 iodination, while dimethyl uracil undergoes C5 iodination. Scope of the method was demonstrated through the rapid synthesis of both electron rich as well as electron poor heteroaromatic iodides. The protocol was found to be scalable and general, while a mechanism has been proposed.

Presently available simplified analytical methods and semi-empirical methods for the analysis of buried pipelines subjected to fault motion are suitable only for the strike-slip and the normal-slip type fault motions, and cannot be used for the reverse fault crossing case. A simple finite element model, which uses beam elements for the pipeline and discrete nonlinear springs for the soil, has been proposed to analyse buried pipeline subjected to reverse fault motion. The material nonlinearities associated with pipe-material and soil, and geometric nonlinearity associated with large deformations were incorporated in the analysis. Complex reverse fault motion was simulated using suitable constraints between pipe-nodes and ground ends of the soil spring. Results of the parametric study suggest that the pipeline's capacity to accommodate reverse fault offset can be increased significantly by choosing a near-parallel orientation in plan with respect to the fault line. Further improvement in the response of the pipeline is possible by adopting loose backfill, smooth and hard surface coating, and shallow burial depth in the fault crossing region. For normal or near normal orientations, pipeline is expected to fail due to beam buckling at very small fault offsets.

The effect of damage at the cohesive concrete—laminate interface on failure of FRP-reinforced concrete columns is considered. Analytical expressions, obtained for the shear stress at the interfacial bond, show that higher fabric thickness and strength result in higher interfacial shear. Hence, as fabric thickness and strength are increased, there is increased likelihood of distress in the bond due to high shear stresses. In case of damage at the interface, the nature of the interfacial bond may change and thus affect the failure load. Damage in the bond is modeled to allow transition from cohesive bond to unbonded contact, using stress-based damage initiation and energy-based damage evolution. Bond failure, resulting in damage to the surface concrete, is found to facilitate failure by fabric rupture through three distinct mechanisms.

This paper examines the buckling of a column with an internal hinge that is retrofitted with a rotational spring to restore some capacity to carry bending moment at the internal hinge location. The problem is solved analytically to obtain the critical buckling load. In addition a numerical solution is obtained using finite elements with the help of the ABAQUS finite-element analysis software. The results are compared, and design curves are obtained that yield the critical buckling load for the column for various values of the rotational spring stiffness and internal hinge location. The increase in strength of the column with the internal hinge wrapped with one or more layers of reinforcing material is then studied. An analytical expression is found to characterize the reinforcing wrap in terms of the stiffness of an equivalent linear elastic rotational spring. The procedure is validated by a finite-element analysis.

In this paper the failure of a three layer system comprising a concrete column, an intermediate epoxy layer, and fiber-reinforced polymer (FRP) confinement is investigated. We perform a series of numerical experiments to investigate how the failure loads and ultimate strains of axially loaded plain cement concrete (PCC) and reinforced cement concrete (RCC) columns change with the type of the bond between concrete and epoxy and between epoxy and FRP. Three types of interfacial behavior are considered: rigid, cohesive compliant, and unbonded contact. An idealized spring model for the resultant confinement stiffness is used to explain the effect the nature of the bond has on the results. It is found that the type of bond has a significant effect on the ultimate strength of PCC columns. The results also indicate that the presence of longitudinal and hoop steel reinforcement allows use of comparatively less stiff FRP sheets as confinement material for RCC columns.

The effect of laminate thickness on crack pattern, mode of failure, and strength of shear deficient reinforced concrete (RC) T-beams wrapped with glass fiber reinforced polymer (GFRP) laminates was studied experimentally and numerically. Eight specimens of 2.5 m span, designed to fail in shear, were tested for two point static loading. Displacements, strains, and crack pattern were monitored. The strength and mode of failure were found to depend on the crack pattern. For U wraps, increasing the fiber reinforced polymer (FRP) laminate thickness resulted in reduced web cracking and increased cracking near the free edge of the laminate.

A novel graphene oxide (GO)-immobilized heteroleptic iridium complex was synthesized and demonstrated as a first heterogenized homogeneous catalyst for the production of dimethylformamide (DMF) from carbon dioxide, hydrogen, and dimethylamine. The synthesized hybrid catalyst showed comparable activity as homogeneous heteroleptic iridium complex with additional benefits such as facile recovery and recycling of the catalyst. After completion of the reaction, the heterogeneous catalyst was easily recovered by filtration, and reused for subsequent recycling processes without any significant change in the catalytic efficiency. (C) 2016 Elsevier Ltd. All rights reserved.

This Pd-catalyzed, chelation-assisted C-H olefination between unactivated, aliphatic olefins and phenylacetic acid substrates reveals a broad substrate scope, which is enabled by a bidendate directing group together with the use of the racemic binaphthyl ligand to enhance the catalytic activity of the Pd(II) species.

Site-selective C-H functionalization has emerged as an efficient tool in simplifying the synthesis of complex molecules. Most often, directing group (DG)-assisted metallacycle formation serves as an efficient strategy to ensure promising regioselectivity. A wide variety of ortho- and meta-C-H functionalizations stand as examples in this regard. Yet despite this significant progress, DG-assisted selective para-C-H functionalization in arenes has remained unexplored, mainly because it involves the formation of a geometrically constrained metallacyclic transition state. Here we report an easily recyclable, novel Si-containing biphenyl-based template that directs efficient functionalization of the distal p-C-H bond of toluene by forming a D-shaped assembly. This DG allows the required flexibility to support the formation of an oversized pre-transition state. By overcoming electronic and steric bias, para-olefination and acetoxylation were successfully performed while undermining o- and m-C-H activation. The applicability of this D-shaped biphenyl template-based strategy is demonstrated by synthesizing various complex molecules.

Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki–Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct olefination of aryl carbon–hydrogen (C–H) bonds (Fujiwara–Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C–H bond olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C–H olefination for synthesizing divinylbenzene derivatives.